<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>2_原生事件绑定</title>
</head>
<body>
    <button id="btn1">按钮1</button>
    <button id="btn2">按钮2</button>
    <button onclick="demo()">按钮3</button>
    
    <script type="text/javascript">
        const btn1 = document.getElementById('btn1')
        btn1.addEventListener('click', ()=>{
            alert('按钮1被点击了!')
        })

        const btn2 = document.getElementById('btn2')
        btn2.onclick = ()=> {
            alert('按钮2被点击了')
        }

        function demo(){
            alert('按钮3被点击了')
        }
    </script>
</body>
</html>